The invention relates to a paper discharge control method of an image forming apparatus having an intermediate tray and more particularly to a paper discharge control method applied to an image forming apparatus in which after the paper which is provided with a first image forming process is guided into the intermediate tray, the paper is taken out from the intermediate tray and provided with the image forming process again, and is guided to a specified bin.
In an image forming apparatus of an electrostatic copying machine and the like, there has been a strong demand for multiple functions In recent years, there is provided an image forming apparatus which has what is called a duplex image forming function whereby an image forming is provided on both sides of a sheet of paper or what is called an editing function whereby an image forming which corresponds to two or more sheets of originals is provided on a sheet of paper.
In order to form an image on a plurality of sheets of paper using a duplex image forming function or an editing function such as above and to sort the paper into a sorter, the following methods are adopted. These methods will hereinafter be explained by referring to the case of the duplex copying. (When an editing function is adopted, it is only different mainly in that the copy paper to be guided into the intermediate tray is reversed as compared with a duplex copying function, and basically the following description can be applied.)
That is to say, it is a method in which an ordinary copying operation is caused to be provided over the obverse side of a copy paper, the copy paper whose image copying has been completed is guided in order into the intermediate tray, then sent into the copying section again, thereby causing other copying operation to be provided on the reverse side of the copy paper.
The method will further be described in detail. A plurality number of sheets of paper is set in advance by manual operation, copy paper is sent in order from a paper feeding cassette and the like to be provided with copying process corresponding to that of an original document, and those sheets of copy paper are taken once into an intermediate tray. Then, an original document is exchanged or a both-sided document is turned over, a specified key (usually a print key) is operated to take out the copy paper in order from the intermediate tray, and the copy paper is provided with the copying process again, and then guided into a specified bin in a sorter. (In the case the sort mode is selected, the copy paper is guided into a sort bin, and in the case the sort mode is not selected, the copy paper is guided into a non-sort bin.) In a manner as described above it is possible to provide a copying operation with both sides of the copy paper.
In the above electrostatic copying apparatus, if no overlapped feeding (in which more than two sheets of the copy paper are overlapped and conveyed) occurs at all while the copy paper is being guided from the paper feeding cassette into the intermediate tray in order to accomplish a first copying process, it is possible to cause a second copying process to be carried out without any inconvenience with respect to one sheet of the copy paper. If, however, an overlapping has occurred, it results in that there exists the copy paper more than the set number in the intermediate tray and that the copy paper remains in the intermediate tray at the time the second copying process is completed.
Therefore, in the case where the copy paper remains in the intermediate tray, there has been adopted conventionally either of the following methods.
(A): An all clear key is operated, and automatically or by manual operation in the same manner as a jam process, the copy paper is taken out from the intermediate tray.
(B): The copying process is carried out unconditionally for all of the copy paper which exists in the intermediate tray, thus taking out the copy paper. (See pages 28 and 29 of Japanese Patent Application No. 171347/1979.)
In addition, if no overlapped feeding has occurred at all while the copy paper is taken out from the intermediate tray in order to carry out the second copying process, it is possible to respectively perform the second copying process against the necessary number of paper without causing any inconvenience, but in case the overlapped feeding has occurred, there does not exist copy paper in the intermediate tray even if an attempt is made to carry out the copying processes as many times as the necessary number of the copy paper.
In the case it is detected that the copy paper does not exist in the intermediate tray, either of the following methods is used to be adopted.
(C): A method for causing the copying process to be stopped forcibly.
(D): A method for causing a series of the next copying cycle to be carried out.
In the above case (A), when the copy paper remaining in the intermediate tray is taken out forcibly, the data for copying, which is set in the electrostatic copying apparatus and the sorter, is caused to be reset, and before carrying out the copying operation, it becomes necessary to accomplish resetting operation of the data such as the size of the copy paper, the number of copy to be made, and the density of the copy which are necessary for the copying operation. Also, a setting operation of the data necessary for the sorter becomes necessary, which in turn impairs the operational performance.
In the above case (B), because the copying is also accomplished with respect to the copy paper remaining in the above intermediate tray, the total number of the copy paper to be taken out will be more than the set number of sheets of the copy paper. Therefore, when the sorter is used, the copy paper which remained in the intermediate tray is sorted into the sort bin to which the first copy paper which corresponds to the next original document should have been sorted and the first copy paper which is copied with the next original document is actually sorted into the second sort bin. As the result thereof, despite of carrying out the desired sorting by the sorter, incorrectly collated or irregularly sorted copied paper will be obtained, and considerable time will be required for truing up the copied paper by manual work.
In the above case (C), when the all clear key or the like is operated to reset the stopping status forcibly so as to make it possible to execute the copying process again, the electrostatic copying apparatus and the sorter are caused to be reset necessitating the setting operation of the data necessary for the electrostatic copying apparatus as well as the setting operation of the data necessary for the sorter prior to carrying out the copying operation again. This results that operational performance is considerably impared.
In the above case (D), even though the number of the copy paper (in case the overlapped feeding occurs, because the overlapped sheets of paper are guided to the sort bin together, they are counted as one sheet of the copy paper) to be guided to the sorter is less than the set number, the sorter is controlled based on the set number of the copy paper. Therefore, as in the case of the above (B), despite of carrying out the desired sorting by the sorter, the sorted sheets of copied paper obtained consequently become irregular and it takes much time for truing them up by manual work. (E): In order to overcome the defect of (C), an electrostatic copying apparatus is proposed in which the copying operation is carried out again with respect to the obverse and reverse sides of an original document in accordance with the same data for copying or parameter so as to complete the copying of the set number of the copy paper (refer to Japanese Patent Application No. 171347/1979 on pages 29 and 30).
This proposal (E) will hereinafter be described. For convenience's sake of explanation, the following assumption is made: The set number of the copy paper is designated as n, sort bins as B1, B2, . . . , Bn. It is assumed that overlapped feeding of the copy paper which is taken out form the intermediate tray has occurred and two sheets of copy paper have been sent together to any sort bin Bi (i=1 to n). One of the two sheets of copy paper has been copied with an image on the obverse and reverse sides thereof but the other sheet has been copied with an image only on the obverse side thereof. On the other hand, because the number of the copy paper to be guided into the sorter is short by one sheet, there is no copy paper distributed into the sort bin Bn. According to the above proposal (E), the copying operation is to be provided again with the obverse and reverse sides of an original document and the copied paper is to be sorted into any sorter. By this arrangement, it becomes possible to obtain always as many numbers of copy as required.
However, among the copy paper which has been distributed into the sort bin Bi, the one sheet which is copied with an image only on the obverse side thereof will be wasted without being utilized. The reason of this is that in order to replenish the deficiency, another sheet of copied paper is being produced by newly accomplishing the copying operation with respect to the surface and reverse of an original document. Therefore, if a number of overlapped feeding should occur, wasteful consumption of the copy paper would be resulted.
An object of the present invention is to provide a discharge control method of copy paper in which when taking out the copy paper which remains in the intermediate tray at the time the set number of image forming process is carried out, it is possible to eliminate the data setting operation for the succeeding image formation and to reduce the time for truing up the image-formed paper by manual work.
Another object of the present invention is to provide a discharge control method of copy paper in which when no copy paper exists in the intermediate tray before carrying out the set number of the image forming process, it is possible to reduce the time for sorting the image-formed paper which is obtained by a series of succeeding image forming processes and to prevent wasteful consumption of the copy paper.
In a discharge control method of copy paper according to the present invention for accomplishing the above objects, in the case the copy paper is remaining in the intermediate tray at the time the set number of the image forming process is completed, on condition that a specified key has been operated, the following processes are carried out: The copy paper existing in the above intermediate tray is successively taken out, image forming process is provided thereon, and then the paper thus copied is guided into a bin which has not been used for sorting when the image forming is performed with respect to the above set number of the paper.
If the copy paper still remains in the intermediate tray at the time the set number of the image forming process has been caused to be carried out, it can be judged that overlapped feeding has occurred in the copy paper guided for the first image forming process. Therefore, according to the discharge control method of copy paper described above, only in the case a specified key operation is carried out, the copy paper remaining in the intermediate tray is taken out forcibly in order and provided with the image forming process, then the paper is guided into the bin of the sorter which has not been used for discharging the set number of sheets of copy paper. In this case, it is possible to take out forcibly the remaining paper in a state where the initial data is preserved as it is and to provide the second image formation with respect to the taken out paper, without carrying out the data setting operation anew. Therefore, finally it is possible to obtain the set number of the copied paper which is provided with two or more image forming processes simply by replacing the obtained paper. The embodiments in which two image forming processes are performed are hereby described.
In the discharge control method of the copy paper according to the present invention for accomplishing the other object of the above, in the case there does not exist paper in the intermediate tray before completing the set number of the image forming process, on condition that a specific key operation has been carried out, the image forming operation the number of which is relevant to that of uncopied paper because of overlapped feeding is discontinued, and the sorting operation for the next original starts from a sort bin skipping over some sort bins which should have received the uncopied paper mentioned above.
According to the discharge control method of paper described above, in the case where the paper provided once with the image forming process is guided into the intermediate tray and then the image forming process is provided with the paper which is taken out again from the intermediate tray and guided into the sorter, if there does not exist the paper in the intermediate tray before causing the set number of the image forming process to be carried out, it can be judged that the overlapped feeding is occurring in taking out the paper for the second image forming process. Thus, only in the case where a specified key operation has been carried out, the image forming operation the number of which is relevant to that of uncopied paper because of overlapped feeding is discontinued and the paper feeding for the next image forming process is carried out. In this case, because the sort bin corresponding to the above mentioned discontinued image forming operation is skipped and the paper which corresponds to the next image formation is sorted from the next sort bin, it is possible to precisely guide the image-formed paper obtained by a series of subsequent image forming processes, into the corresponding sort bin.
Therefore, because only the image-formed paper corresponding to a series of image forming processes where overlapped feeding occurred becomes insufficient in any of the sort bin of the sorter, and it is precisely sorted into the desired sort bin with respect to the image-formed paper which corresponds a series of other image forming process, it is possible to reduce the time for truing up the image-formed paper after all the image forming processes have been completed, to the minimum required level. In addition, while truing up operation, by taking out the image-formed paper corresponding to a series of image forming process where the above overlapped feeding has occurred, and by providing the second image forming process, it becomes possible to utilize the paper without wasting it.
The above and other features of the present invention will hereinafter be made further apparent by the following explanations by referring to the attached drawings.